Ultra-high-precision mass sensing can be an important detection method such as for biomolecular and chemical detection. Detecting molecules by mass need not require chemical or fluorescent labeling, which can allow for simplified detection protocols and for sensing in systems adversely affected by labeling. For example, the limited cross reactivity of fluorescently labeled generic binders can limit the specificity of a protein assay, such as used for analyzing or characterizing various cells, biomarkers, or autoimmune diseases, among others. Additionally, use of unbound labeled reporters can also have limitations, such as preventing real-time detection and quantification of binding events, as such unbound reporters must generally be washed away prior to optical interrogation.